Method for observing combustion conditions in a gas turbine engine

Abstract

A fuel injector for a gas turbine combustor is disclosed which includes a feed arm having a flange for mounting the injector within the combustor and a fuel nozzle depending from the feed arm for injecting fuel into the combustor for combustion. An optical sensor array is operatively associated with the fuel nozzle for observing combustor flame characteristics. The optical sensor array includes a plurality of sapphire rods positioned to be close enough to the combustor flame to oxidize soot deposits thereon.

What is claimed is: 
     
       1. A method of removing soot from an optical surface of an optical sensor located within a gas turbine combustor, comprising the steps of:
 a) providing an optical sensor formed from a material that can withstand exposure to a combustor flame; and 
 b) positioning the optical surface of the optical sensor within an air stream emanating from a fuel nozzle, in close proximity to the combustor flame so as to gain flame exposure sufficient to oxidize soot deposits thereon. 
 
     
     
       2. A method according to  claim 1 , further comprising the step of coating the optical surface of the optical sensor with a catalyst that promotes oxidation of soot by lowering the temperature at which oxidation occurs to a temperature below that which the optical surface is exposed. 
     
     
       3. A method according to  claim 1 , further comprising the step of configuring the optical surface of the optical sensor to act as a diffuser. 
     
     
       4. A method according to  claim 3 , further comprising the step of frosting the optical surface of the optical sensor to diffuse light.